misc/mei/hdcp: Repeater topology verification and ack

Request ME to verify the downstream topology information received.

ME FW will validate the Repeaters receiver id list and
downstream topology.

On Success ME FW will provide the Least Significant
128bits of VPrime, which forms the repeater ack.

v2: Rebased.
v3:
  cldev is passed as first parameter [Tomas]
  Redundant comments and cast are removed [Tomas]
v4:
  %zd for ssize_t [Alexander]
  %s/return -1/return -EIO [Alexander]
  Style and typos fixed [Uma]
v5: Rebased.
v6: Rebasing.
v7:
  Adjust to the new mei interface.
  Fix for Kdoc.
v8:
  K-Doc addition. [Tomas]
v9:
  renamed func as mei_hdcp_* [Tomas]
  Inline function is defined for DDI index [Tomas]
v10:
  K-Doc fix. [Tomas]
v11:
  Rebased.
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1550772730-23280-12-git-send-email-ramalingam.c@intel.com

drivers/misc/mei/hdcp/mei_hdcp.c

@@ -466,6 +466,80 @@ static int mei_hdcp_get_session_key(struct device *dev,
 	return 0;
 }
 
+/**
+ * mei_hdcp_repeater_check_flow_prepare_ack() - Validate the Downstream topology
+ * and prepare rep_ack.
+ * @dev: device corresponding to the mei_cl_device
+ * @data: Intel HW specific hdcp data
+ * @rep_topology: Receiver ID List to be validated
+ * @rep_send_ack : repeater ack from ME FW.
+ *
+ * Return: 0 on Success, <0 on Failure
+ */
+static int
+mei_hdcp_repeater_check_flow_prepare_ack(struct device *dev,
+					 struct hdcp_port_data *data,
+					 struct hdcp2_rep_send_receiverid_list
+							*rep_topology,
+					 struct hdcp2_rep_send_ack
+							*rep_send_ack)
+{
+	struct wired_cmd_verify_repeater_in verify_repeater_in = { { 0 } };
+	struct wired_cmd_verify_repeater_out verify_repeater_out = { { 0 } };
+	struct mei_cl_device *cldev;
+	ssize_t byte;
+
+	if (!dev || !rep_topology || !rep_send_ack || !data)
+		return -EINVAL;
+
+	cldev = to_mei_cl_device(dev);
+
+	verify_repeater_in.header.api_version = HDCP_API_VERSION;
+	verify_repeater_in.header.command_id = WIRED_VERIFY_REPEATER;
+	verify_repeater_in.header.status = ME_HDCP_STATUS_SUCCESS;
+	verify_repeater_in.header.buffer_len =
+					WIRED_CMD_BUF_LEN_VERIFY_REPEATER_IN;
+
+	verify_repeater_in.port.integrated_port_type = data->port_type;
+	verify_repeater_in.port.physical_port = mei_get_ddi_index(data->port);
+
+	memcpy(verify_repeater_in.rx_info, rep_topology->rx_info,
+	       HDCP_2_2_RXINFO_LEN);
+	memcpy(verify_repeater_in.seq_num_v, rep_topology->seq_num_v,
+	       HDCP_2_2_SEQ_NUM_LEN);
+	memcpy(verify_repeater_in.v_prime, rep_topology->v_prime,
+	       HDCP_2_2_V_PRIME_HALF_LEN);
+	memcpy(verify_repeater_in.receiver_ids, rep_topology->receiver_ids,
+	       HDCP_2_2_RECEIVER_IDS_MAX_LEN);
+
+	byte = mei_cldev_send(cldev, (u8 *)&verify_repeater_in,
+			      sizeof(verify_repeater_in));
+	if (byte < 0) {
+		dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte);
+		return byte;
+	}
+
+	byte = mei_cldev_recv(cldev, (u8 *)&verify_repeater_out,
+			      sizeof(verify_repeater_out));
+	if (byte < 0) {
+		dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte);
+		return byte;
+	}
+
+	if (verify_repeater_out.header.status != ME_HDCP_STATUS_SUCCESS) {
+		dev_dbg(dev, "ME cmd 0x%08X failed. status: 0x%X\n",
+			WIRED_VERIFY_REPEATER,
+			verify_repeater_out.header.status);
+		return -EIO;
+	}
+
+	memcpy(rep_send_ack->v, verify_repeater_out.v,
+	       HDCP_2_2_V_PRIME_HALF_LEN);
+	rep_send_ack->msg_id = HDCP_2_2_REP_SEND_ACK;
+
+	return 0;
+}
+
 static const __attribute__((unused))
 struct i915_hdcp_component_ops mei_hdcp_ops = {
 	.owner = THIS_MODULE,
@@ -477,7 +551,8 @@ struct i915_hdcp_component_ops mei_hdcp_ops = {
 	.initiate_locality_check = mei_hdcp_initiate_locality_check,
 	.verify_lprime = mei_hdcp_verify_lprime,
 	.get_session_key = mei_hdcp_get_session_key,
-	.repeater_check_flow_prepare_ack = NULL,
+	.repeater_check_flow_prepare_ack =
+				mei_hdcp_repeater_check_flow_prepare_ack,
 	.verify_mprime = NULL,
 	.enable_hdcp_authentication = NULL,
 	.close_hdcp_session = NULL,